1. Field of the Invention
The present invention relates to a magnetic head for a magnetic recording reproducer.
2. Description of the Prior Art
In most two-sided disc recording reproducers employing a magnetic head consisting of an upper head assembly and a lower head assembly, a gimbals head and a button head are used as the upper head assembly and the lower head assembly, respectively, and a magnetic disc is inserted between the upper and lower head assemblies for writing and reading information. The button head is formed by fixing a convex head holder having a head burried therein to a supporting member, while the gimbals head is formed by securing or joining a gimbals spring carrying a head to a supporting member.
FIG. 2 is a sectional view of a conventional magnetic head of such a type. In FIG. 2, there are shown a disc 5, a carriage 100, a lower head 101 fixed to the carriage 100, an arm 102, an upper head 104 attached through a gimbals spring 103 to the arm 102 so as to be swingable, a pivot 105 formed in the arm 102 for supporting the upper head 104, a leaf spring 106 supporting the arm 102 so that the upper head 104 is movably supported opposite to the lower head 101, a holding member 107, and a compression spring 108 interposed betwen the arm 102 and the holding member 107.
FIG. 3 is a plan view of the ginbals spring as viewed from the side of the upper head 104 in FIG. 2. In FIG. 3, there are shown a frame 109, a spring plate 110, a holder 111, a first supporting arm 112, and a second supporting arm 113. The holder 111 fixedly holding the upper head 104 is supported so as to be swingable in the directions indicated by a double-headed arrow A on the first supporting arm 112 and in the directions indicated by a double-headed arrow B on the second supporting arm 113. The holder 111 turns in either of the directions of the double-headed arrow B so that the upper head 104 is aligned correctly with the lower head 101 when the disc 5 is held between the upper head 104 and the lower head 101, even if the arm 102 is tilted to one side or the other. The holder 111 turns in either of the directions of the double-headed arrow A to prevent the upper head 104 tilting in the direction of turning of the arm 102 due to the variation in the thickness of the disc 5 when the disc 5 is held between the upper head 104 and the lower head 101 and to correct the tilt of the arm 102 resulting from the bending of the leaf spring 106 so that the face of the upper head 104 is always parallel to the face of the lower head 101.
A method of assembling the magnetic head of this type will be explained briefely. First, the vertical and horizontal positions, the height and the azimuth of the lower head 101 with respect to the carriage 100 is adjusted finely means of a microscope. The inclination of the lower head 101 with the respect to the carriage 100 is adjusted finely by means of a collimator. Then, the vertical and horizontal positions, the height and the azimuth of the lower head 101 is reconfirmed by means of a microscope, and when readjustment is performed, the inclination of the lower head 101 is reconfirmed by means of a collimator.
Practically, the carriage 100 is secured to the pallet, the lower head 101 is supported so that the position thereof is adjustable and the pallet is transferred between the microscope and the collimator for the above-mentioned fine adjustment. The collimator is a device for measuring the inclination of a surface by projecting a light beas on the surface and detecting the direction of reflection of the light beam. The microscope having a small depth of field is employed for the fine adjustment, and hence it is found that the surface is at a correct height when the surface is in focus.
On the other hand, the upper head 104 is attached to the arm 102 without any adjustment. The vertical and horizontal positions and the azimuth of the upper head 104 is adjusted in attaching the arm 102 to the carriage 100.
Thus such a conventional magnetic head requires very delicate and complicated adjustment in securing the lower head 101 to the carriage 100.